Component wall having diffusion sections for cooling in a turbine engine

Abstract

A film cooling structure formed in a component wall of a turbine engine and a method of making the film cooling structure. The film cooling structure includes a plurality of individual diffusion sections formed in the wall, each diffusions section including a single cooling passage for directing cooling air toward a protuberance of a wall defining the diffusion section. The film cooling structure may be formed with a masking template including apertures defining shapes of a plurality of to-be-formed diffusion sections in the wall. A masking material can be applied to the wall into the apertures in the masking template so as to block outlets of cooling passages exposed through the apertures. The masking template can be removed and a material may be applied on the outer surface of the wall such that the material defines the diffusion sections once the masking material is removed.

What is claimed is: 
     
       1. A component wall in a turbine engine comprising:
 a substrate having a first surface and a second surface opposed from said first surface; 
 a plurality of diffusion sections located in said second surface, each said diffusion section defined by a bottom surface between said first and second surfaces, an open top portion located at said second surface, and wall structure extending outwardly continuously from said bottom surface to said second surface, said wall structure surrounding the respective diffusion section and comprising at least a first sidewall, a second sidewall opposed from said first sidewall, a third sidewall extending between said first and second sidewalls, and a fourth sidewall opposed from said third sidewall and extending between said first and second sidewalls, said third and fourth sidewalls diverging from each other; 
 wherein:
 said bottom surface of each said diffusion section is substantially parallel to said second surface, said bottom surface extending from said first sidewall to said second sidewall and from said third sidewall to said fourth sidewall; 
 said first sidewall of each said diffusion section comprises a protuberance extending toward said second sidewall of the respective diffusion section, each said protuberance formed by a pair of diverging wall portions, said diverging wall portions diverging from each other at a greater angle than an angle of divergence of said third and fourth side walls and intersecting said third and fourth sidewalls at respective downstream junctions; 
 each said diffusion section comprises a single cooling passage, said cooling passage of each said diffusion section extending through said substrate from said first surface to said bottom surface of the respective diffusion section, wherein an outlet of each said cooling passage is arranged within the respective diffusion section such that cooling air exiting each said cooling passage through said outlet is directed toward said protuberance of the respective first sidewall; and 
 said outlet of said cooling passage includes opposed first and second side edges, said first side edge being generally parallel to said third sidewall of said respective diffusion section and said second side edge being generally parallel to said fourth sidewall of said respective diffusion section. 
 
 
     
     
       2. The component wall of  claim 1 , wherein said first and second sidewalls of said wall structure of each said diffusion section are substantially perpendicular to said second surface. 
     
     
       3. The component wall of  claim 1 , wherein said protuberance of said first sidewall of each said diffusion section comprises an apex formed by said diverging wall portions and aligned with an outlet of a respective cooling passage to effect a diverging flow of cooling air along said first sidewall to said junctions, and wherein at least one of said protuberances is defined by a curved wall section of said first sidewall, said apex of the respective protuberance defined by a portion of said curved wall section located closest to said second sidewall. 
     
     
       4. The component wall of  claim 1 , wherein said protuberance of said first sidewall of each said diffusion section comprises an apex formed by said diverging wall portions and aligned with an outlet of a respective cooling passage to effect a diverging flow of cooling air along said first sidewall to said junctions. 
     
     
       5. A component wall in a turbine engine comprising:
 a substrate having a first surface and a second surface opposed from said first surface; 
 a plurality of diffusion sections located in said second surface, each said diffusion section defined by a bottom surface between said first and second surfaces, an open top portion located at said second surface, and wall structure extending outwardly continuously from said bottom surface to said second surface, said wall structure surrounding the respective diffusion section and comprising a first sidewall, a second sidewall opposed from said first sidewall, a third sidewall extending between said first and second sidewalls, and a fourth sidewall opposed from said third sidewall and extending between said first and second sidewalls, said third and fourth sidewalls diverging from each other; 
 wherein:
 said bottom surface of each said diffusion section is substantially parallel to said second surface and extends from said third sidewall to said fourth sidewall; 
 said first sidewall of each said diffusion section is substantially perpendicular to said second surface and comprises a protuberance extending toward said second sidewall of the respective diffusion section, each said protuberance formed by a pair of diverging wall portions, said diverging wall portions diverging from each other at a greater angle than an angle of divergence of said third and fourth side walls and intersecting said third and fourth sidewalls at respective downstream junctions; 
 each said diffusion section comprises a single cooling passage, said cooling passage of each said diffusion section extending through said substrate from said first surface to said bottom surface of the respective diffusion section, wherein an outlet of each said cooling passage is arranged within the respective diffusion section such that cooling air exiting each said cooling passage through said outlet is directed toward an apex of the respective protuberance to effect a diverging flow of cooling air along said respective first sidewall; and 
 said outlet of said cooling passage includes opposed first and second side edges, said first side edge being generally parallel to said third sidewall of said respective diffusion section and said second side edge being generally parallel to said fourth sidewall of said respective diffusion section. 
 
 
     
     
       6. The component wall of  claim 5 , wherein at least one of said protuberances is defined by one of:
 a curved wall section of said first sidewall, said apex of the respective protuberance defined by a portion of said curved wall section located closest to said second sidewall; and 
 a pair of wall sections of said first sidewall that extend at an angle relative to each other and come together at said apex. 
 
     
     
       7. A method of forming cooling structure in a component wall of a turbine engine comprising:
 masking an outer surface of an inner layer of the component wall with a masking template, said masking template including apertures defining shapes of a plurality of to-be-formed diffusion sections in the component wall, the apertures spaced from each other corresponding to spacing between outlets of cooling passages extending through the inner layer of the component wall such that the outlets of the cooling passages are exposed through the apertures; 
 applying a masking material to the component wall into the apertures in the masking template so as to block the outlets of the cooling passages; 
 removing the masking template; 
 applying a material on the outer surface of the inner layer to form an outer layer of the component wall over the inner layer, the outer layer surrounding the plurality of to-be-formed diffusion sections in the component wall; 
 removing the masking material from the component wall such that a plurality of diffusion sections are formed in the component wall where the masking material was previously located, wherein each diffusion section is defined by:
 a bottom surface corresponding to the surface area of the outer surface of the inner layer of the component wall where the masking material was previously located, wherein the bottom surface is substantially parallel to an outer surface of the outer layer of the component wall; 
 a first sidewall defined by the material forming the outer layer of the component wall; 
 a second sidewall spaced from the first sidewall and defined by the material forming the outer layer of the component wall; 
 a third sidewall extending between the first and second sidewalls; and 
 a fourth sidewall opposed from the third sidewall and extending between the first and second sidewalls, the fourth sidewall diverging from the third sidewall; 
 
 wherein: 
 the outlet of each cooling passage includes opposed first and second side edges, the first side edge being generally parallel to the third sidewall of the respective diffusion section and the second side edge being generally parallel to the fourth sidewall of the respective diffusion section; 
 the first sidewall of each diffusion section comprises a protuberance extending toward the second sidewall of the respective diffusion section, each protuberance formed by a pair of diverging wall portions, the diverging wall portions diverging from each other at a greater angle than an angle of divergence of the third and fourth side walls and intersecting the third and fourth sidewalls at respective downstream junctions; and 
 said first, second, third, and fourth sidewalls surround each diffusion section and extend outwardly continuously from said bottom surface to said outer layer, said bottom surface of each diffusion section extending from said third sidewall to said fourth sidewall. 
 
     
     
       8. The method of  claim 7 , wherein the first sidewall is substantially perpendicular to the bottom surface. 
     
     
       9. The method of  claim 8 , wherein:
 the third sidewall of each diffusion section is substantially perpendicular to the bottom surface thereof; 
 the fourth sidewall of each diffusion section is substantially perpendicular to the bottom surface thereof; and 
 the second sidewall of each diffusion section is substantially perpendicular to the bottom surface thereof and the bottom surface of each diffusion section extends from the third sidewall to the fourth sidewall thereof. 
 
     
     
       10. The method of  claim 8 , wherein the protuberance in each of the first sidewalls is aligned with an outlet of a respective cooling passage. 
     
     
       11. The method of  claim 7 , further comprising, prior to applying the material on the outer surface of the inner layer, applying a bond coat to the outer surface of the inner layer of the component wall, and wherein applying a material on the outer surface of the inner layer comprises applying a thermal barrier coating on the bond coat. 
     
     
       12. The method of  claim 7 , further comprising, subsequent to applying a masking material and prior to applying the material on the outer surface of the inner layer, curing the masking material. 
     
     
       13. The component wall of  claim 1 , wherein said third and fourth sidewalls of each said diffusion section diverge away from each other as they extend away from said second sidewall. 
     
     
       14. The component wall of  claim 13 , wherein said third and fourth sidewalls of each said diffusion section are angled about 10 degrees relative to an axis of said cooling passage associated with said respective diffusion section. 
     
     
       15. The component wall of  claim 1 , wherein said diffusion sections have different exit portion shapes than exit portion shapes of said cooling passages associated with the respective diffusion sections. 
     
     
       16. The component wall of  claim 5 , wherein said third and fourth sidewalls of each said diffusion section diverge from each other as they extend away from said second sidewall. 
     
     
       17. The component wall of  claim 16 , wherein said third and fourth sidewalls of each said diffusion section are angled about 10 degrees relative to an axis of said cooling passage associated with said respective diffusion section. 
     
     
       18. The component wall of  claim 5 , wherein said diffusion sections have different exit portion shapes than exit portion shapes of said cooling passages associated with the respective diffusion sections.